Tube forming methods can be used for efficient transition in the production of tubes having varying thickness. Material used to form consecutive tubes may have the same thickness along a separation plane separating a first discrete section from a second discrete section of the material, and the first discrete section and the second discrete section may each have varying thickness in a feed direction of the material. With such a thickness profile, the first discrete section of the material may be formed into a first cylinder having varying thickness and separated from the second discrete portion as the second discrete section is formed into a second cylinder having varying thickness. In particular, the transition between the first cylinder and the second cylinder may be achieved without scrap and/or interruption, resulting in cost-savings and improvements in production throughput associated with forming tubes having varying thickness.

A process for winding a convolutely wound tubular structure having a machine direction, a cross-machine direction coplanar thereto, and a Z-direction orthogonal to both the machine- and cross-machine directions is disclosed.

A helically wound tubular structure is disclosed. The tubular structure has a first sheet metal helically wound about a longitudinal axis, a second sheet metal having voids disposed therein helically wound about the longitudinal axis and coaxially about the first sheet metal, and a third sheet metal helically wound about the longitudinal axis and coaxially about the first sheet metal and the second sheet metal.

A tubular structure is disclosed. The tubular structure has a first sheet metal having a machine direction. The first sheet metal is convolutely wound about a longitudinal axis and has a tail portion. The tail portion of the first sheet metal is disposed upon and bonded to an immediately subjacent convolution of the first sheet metal.

An elongate tubular structure is disclosed. The elongate tubular structure has a first and second tubular structure wherein a first end of the first tubular structure is matingly and fasteningly engaged to a first end of the second tubular structure. The first and second tubular structures each have a first sheet metal having a machine direction being convolutely wound about a first longitudinal axis. The first sheet metal has a tail portion that is disposed upon and bonded to an immediately subjacent convolution of the first sheet metal to form the respective first and second tubular structures.

An electric-resistance-welded stainless clad steel pipe or tube that is excellent in both the fracture property of the weld and the corrosion resistance of the pipe or tube inner surface as electric resistance welded without additional welding treatment such as weld overlaying after electric resistance welding is provided. An electric-resistance-welded stainless clad steel pipe or tube comprises: an outer layer of carbon steel or low-alloy steel; and an inner layer of austenitic stainless steel having a predetermined chemical composition, wherein a flatness value h/D in a 90 flattening test in accordance with JIS G 3445 is less than 0.3, and a pipe or tube inner surface has no crack in a sulfuric acid-copper sulfate corrosion test in accordance with ASTM A262-10, Practice E, where h is a flattening crack height (mm), and D is a pipe or tube outer diameter (mm).

Tube forming methods can be used for efficient transition in the production of tubes having varying thickness. Material used to form consecutive tubes may have the same thickness along a separation plane separating a first discrete section from a second discrete section of the material, and the first discrete section and the second discrete section may each have varying thickness in a feed direction of the material. With such a thickness profile, the first discrete section of the material may be formed into a first cylinder having varying thickness and separated from the second discrete portion as the second discrete section is formed into a second cylinder having varying thickness. In particular, the transition between the first cylinder and the second cylinder may be achieved without scrap and/or interruption, resulting in cost-savings and improvements in production throughput associated with forming tubes having varying thickness.

An electric-resistance-welded stainless clad steel pipe or tube that is excellent in both the fracture property of the weld and the corrosion resistance of the pipe or tube inner surface as electric resistance welded without additional welding treatment such as weld overlaying after electric resistance welding is provided. An electric-resistance-welded stainless clad steel pipe or tube comprises: an outer layer of carbon steel or low-alloy steel; and an inner layer of austenitic stainless steel having a predetermined chemical composition, wherein a flatness value h/D in a 90 flattening test in accordance with JIS G 3445 is less than 0.3, and a pipe or tube inner surface has no crack in a sulfuric acid-copper sulfate corrosion test in accordance with ASTM A262-10, Practice E, where h is a flattening crack height (mm), and D is a pipe or tube outer diameter (mm).

A steel member, a hot-rolled steel sheet to be used as a material thereof, and production methods therefor are provided. A steel member contains 0.010% to 0.120% Ti, in which 0.005% or more of Ti is precipitated as a precipitate having a particle size of 20 nm or less in the microstructure. A hot-rolled steel sheet for the steel member contains 0.010% to 0.120% Ti, in which 0.005% or more of Ti is present as dissolved Ti in the microstructure. A method for producing the steel member includes subjecting a hot-rolled steel sheet to forming processing and then performing heat treatment including heating to a temperature of higher than 550 C. and 1,050 C. or lower and then cooling at an average cooling rate of 10 C./s or more in the temperature range of 550 C. to 400 C.

A flanged ring connector (50) for connecting adjacent ends of HVAC ducting (52) includes an insertion flange portion to engage within the interior of the ducting. A mating flange portion (56) extends laterally or transversely to the insertion flange portion (54). A seat (58) is formed along the mating flange portion (56) to receive and retain a seal (60) and/or a reinforcing member or bead (90).